<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body></body>
  <script>
    //array  -- object
    //object -- object
    //日期date -- object
    //正则 -- object
    //functio -- function
    //null 空对象 ---object
    //undefined --- undefined
    // var n = function () {}
    // console.log(typeof undefined)
    // var n
    // // ...
    // // 。。。
    // n = null
    // console.log(n)

    // var num = 123
    // var num1 = +num
    // var num2 = Number(num)
    // console.log(typeof num, typeof num1, typeof num2)
    // var str = String(num)
    // console.log(typeof str)

    for (var i = 1; i <= 10; i++) {
      console.log('公交车出站了 第' + (i + 1) + '次')
      console.log('公交车到站了')
      console.log('公交车老太太上车了')
    }
    //循环
  </script>
</html>
